Relevant sampling in finitely generated shift-invariant spaces

Abstract: We consider random sampling in finitely generated shift-invariant spaces $V(\Phi) \subset {\rm L}^2(\mathbb{R}^n)$ generated by a vector $\Phi = (\varphi_1,\ldots,\varphi_r) \in {\rm L}^2(\mathbb{R}^n)^r$. Following the approach introduced by Bass and Gr\"ochenig, we consider certain relatively compact subsets $V_{R,\delta}(\Phi)$ of such a space, defined in terms of a concentration inequality with respect to a cube with side lengths $R$. Under very mild assumptions on the generators, we show that for $R$ sufficiently large, taking $O(R^n log(R^{n^2/\alpha'}))$ many random samples (taken independently uniformly distributed within $C_R$) yields a sampling set for $V_{R,\delta}(\Phi)$ with high probability. Here $\alpha' \le n$ is a suitable constant.We give explicit estimates of all involved constants in terms of the generators $\varphi_1, \ldots, \varphi_r$.